Valves are used to regulate or control fluid flow through an opening. Fluid flow control or regulation is typically achieved by the use of a common valve, such as a flap, lid, or plug which may be closed or clamped to restrict fluid flow or may be opened or released to permit fluid flow. Another common type of valve is a gate valve that opens and closes by rotating pivotally around a hinge. The gate valve is opened by placing the gate in a position parallel to the fluid movement to permit fluid flow. Fluid flow is restricted or prohibited when the gate is positioned perpendicular to the fluid movement.
The problem that exists with common or conventional valves, however, is that they are typically not very fast acting because of the amount of time that it takes to turn or clamp the valve. As a result, a small amount of fluid is permitted to flow past the valve as it is initially opened, and the amount of fluid flow past the valve gradually increases to a maximum level as the valve continues to be opened. The same flow characteristics occur in reverse as fie valve is moved to a closed position.
A need exists in the gas turbine industry for a valve that completely opens and closes very fast and permits a large volume of fluid to flow when open and minimizes residual fluid flow when closed. Air flow disturbances occur in the compressor rotors of a gas turbine engine causing undesirable conditions such as "surge" or "stall" which reduce engine performance and may cause severe mechanical damage to the engine. Such conditions may be catastrophic if they occur in an aircraft turbine engine while the aircraft is in flight. Research has indicated, however, that such flow disruptions in compressor rotors may be delayed by locally affecting the air flow conditions of the critical compressor stage rotor.
The air flow conditions may be locally modified by bleeding air from behind the effected rotor or by injecting air in front of the effected rotor. This modification results in improved performance of the compression system. Successful control of flow disruptions allows improved performance of turbine engines and reduces operating, replacement, and repair costs. An injection valve to inject air in front of a rotor or a bleed valve to extract air behind a rotor, however, must be able to cycle from full close to full open to full close at a very fast speed (approximately 150 Hz), and the valve must be able to pass approximately 1.65 cubic feet of air per second at standard day conditions. Therefore, fast acting high output valves and valve assemblies are desired and have been developed.
U.S. Pat. No. 5,485,868 discloses a fast acting high output valve assembly comprising a number of valves and base openings that are each generally shaped like individual "pie" pieces. The individual pie-piece shaped valves and base openings are generally arranged in a circular geometry. An actuator rod is used to apply a force to the pivoting ends of the pie-piece shaped valves at the center portion of the valve assembly to cause the periphery of the individual pie-piece shaped valves to pivot upwardly to expose the base openings. Each pie-piece shaped valve has a relatively large surface area which generates a relatively large amount of resistance as the valve is subjected to a pressurized fluid. Therefore, the valves require a greater amount of applied force in order to open them. This prior art patent is incorporated by reference herein.
FIG. 9 shows a prior art fast acting high output valve assembly 90 wherein the individual pie-piece shaped valves 92 have relatively large surface areas. Since the valves 92 have relatively large surface areas, the valves 92 are more difficult to open against the resistance generated by a highly pressurized fluid which generally forces the valves 92 into closed positions. Also, the volume of fluid that is able to flow through the valve assembly 90 is somewhat more limited because the individual pie-piece shaped valves 92 and base openings 96 when they are in their open positions provide and are limited to only three fluid flow gap areas A, B, and C (i.e. a single outer radius gap area A and two side gap areas B and C) for fluid to flow therethrough. Furthermore, the sizes of the side gap areas B and C decrease substantially from the opening end 98 towards the pivoting end 102 of the valve 92 thereby the efficiency of the fluid flow through these gap areas B and C decreases towards the pivoting end 102 (i.e. not necessarily the most efficient design for maximizing fluid flow through the gap areas). Therefore, in order to provide better fluid flow efficiency, there is the need and desire to provide a larger number of fluid flow areas and/or larger sized fluid flow areas.
A need exists for a fast acting high output valve assembly that has individual valves with minimal surface area so that they are able to be more easily opened against the resistance of external fluid pressure. It is also needed and desired that the valves and valve assembly have a greater number of fluid flow gap areas and that are also larger in size for allowing a larger volume of fluid to flow therethrough when the valves are placed into their open positions.
Therefore, the present invention discloses and provides an improved fast acting high output valve(s) and valve assembly, and the present invention overcomes the problems, disadvantages, and limitations of the prior art.